Thermally conductive interface materials are widely utilized in the electronics industry for operably coupling heat-generating electronic components to heat-sinking structures. Most typically, such thermally conductive interface materials are utilized in connection with heat-generating electronic components such as integrated circuits (IC), central processing units (CPU), and other electronic components containing relatively high-densities of conductive traces and resistor elements. In particular, the thermal interface materials are oftentimes utilized to operably couple such heat-generating electronic devices to heat-sinking structures, such as finned heat sink structures. In such a manner, excess thermal energy generated by the electronic components may be expelled to the heat sinking structures via the thermal interface material.
Certain electronic devices, in addition to generating excess thermal energy, create electromagnetic radiation across various frequencies. Such radiation can have the effect of causing electromagnetic interference (EMI) upon other electronic devices susceptible to and/or tuned to received electromagnetic wave forms. Devices sensitive to electromagnetic interference include, for example, cellular phones, portable radios, laptop computers, and the like.
As the prevalence of portable electronic devices which are sensitive to electromagnetic interference increases, manufacturers of internal electronic componentry for such devices have incorporated electromagnetic radiation-absorbing substances into thermally conductive interface materials disposed adjacent to the electromagnetic radiation-producing devices. Constructions have therefore been implemented in thermal interface materials which bear an operating characteristic of absorbing, reflecting, or otherwise suppressing the transmittance of electromagnetic radiation through the interface. As a result, such thermal interface material constructions act to provide a thermal release pathway while simultaneously suppressing transmittance of electromagnetic radiation from the corresponding electronic component to which the thermal interface material is addressed.
The thermal interface material constructions proposed to date for providing such characteristics, however, utilize homogenous or quasi-homogenous dispersions of thermally conductive and radiation suppression particles within the thermal interface material backbone matrix. The resultant compositions, particularly at low total filler loading volume fractions (e.g. ≦50 vol. %), have limited thermal conductivity and electromagnetic interference suppression capabilities. At such total filler loading volume fractions, which are often necessary to achieve the desired mechanical properties, it is difficult to simultaneously achieve high thermal conductivity and electromagnetic radiation suppression. As electronic components increase in power, as well as in packing densities, the need arises to enhance thermal transfer and electromagnetic suppression capabilities in thermal interface materials.
It is therefore an object of the present invention to provide an interface product with superior thermal conductivity and electromagnetic interference suppression properties over that which is conventionally available.